The present invention generally relates to clamping mechanisms for clamping a movable carriage carrying a recording/reproducing head of an information recording/reproducing apparatus which records and/or reproduces an information signal on and from a disk-shaped rotary recording medium, and particularly to a clamping mechanism used in such an information recording/reproducing apparatus for restricting a movement of the carriage during transport of the apparatus or during a time in which the apparatus is not used.
An information recording/reproducing apparatus referred to hereinafter simply as an apparatus used for recording and/or reproducing an information signal on and from a disk-shaped rotary information recording medium generally has a carriage on which an information recording/reproducing head such as a magnetic or optical head is provided. The carriage is movable along a radial direction of the information recording medium and transports the head along a radial direction of the disk-shaped rotary information recording medium referred to hereinafter simply as a disk and the recording or reproducing is made along a spiral or concentric track defined on the disk.
As the tracks defined on the disk are separated each other by an extremely minute distance in the order of microns or less, the carriage has to move the recording/reproducing head carried thereon with an extreme precision. For such a carriage, external shock or vibration such as the one applied at the time of transportation or delivery of the apparatus is naturally harmful. Because of this, the information recording/reproducing apparatus has a clamping mechanism for preventing the movement of the carriage during the transportation or delivery of the apparatus.
Conventional clamping mechanism may be classified into following categories:
(1) A screw connecting the carriage to a chassis of the apparatus when tightened at the time of transport or delivery of the apparatus. When tightened, the screw firmly fixes the carriage to the chassis while when performing the recording or reproducing operation, the screw has to be removed from the carriage. PA1 (2) A clamping mechanism comprising a swing lever rotated between a first position in which the carriage is clamped and a second position in which the clamp of the carriage is released, and a clamp pin on the swing lever which engages with a corresponding depression defined on the carriage when the lever is in the first position and which disengages from the depression when the lever is in the second position. PA1 (3) A clamping mechanism comprising an electromagnetic solenoid which clamps the carriage by a clamping member connected thereto when the electromagnetic solenoid is deenergized and releases the clamp when the solenoid is energized.
However, the first mentioned clamping mechanism has a problem in that, once the screw is removed, the carriage cannot be clamped unless the screw is re-mounted manually by the user. Such a re-mounting of the clamping screw on the apparatus is a tedious work as the user has to move the carriage to a predetermined position ready for screwing the carriage on the chassis of the apparatus in which the screw is accepted in a grooved hole in the chassis through a penetrating hole in the carriage. Further, the screw is often lost during the time in which the screw is removed.
Further, there is a problem in the first and second clamping mechanisms that the user sometimes forgets the removal of the screw or rotation of the lever to the second position. When such a situation arises, the head carriage does not move in spite of the operation of the apparatus and the user may mistakenly decide that the apparatus is in failure. In the third clamping mechanism, there is a problem that the cost of the mechanism is increased as a result of the use of expensive electromagnetic solenoid and that the electrical power consumed by the apparatus is increased when operating the apparatus.